'03 F350 SD Dually, 6.0 PSTD
FYI to the community... I posted here a few weeks ago about an unusual cold-start issue. Original post . Truck started normally, 100% reliable, as long as above 40 degrees. But, when colder, no-start. Well, it's been resolved. It wasn't batteries, block heater, starter, fuel, nothing under the hood. It was a $10 relay in the fuse panel under the steering column. Relay #307 in your owners manual. This relay was failing when cold. Another FTE poster suggested checking the relay, also.

My real beef - Ford dealer was NO HELP. I resolved this on my own. I told the dealer what I suspected, and asked them to service it. They responded that they couldn't do anything unless there was a failure code, and wanted to re-flash the PCM. They also said that there's no way anything under the dash would cause a no-start, and insisted on doing expensive stuff under the hood. I told 'em no-thanks.
Here's how I isolated the problem: On a recent cold night, I plugged in the block heater, and put a space heater on the driveway under the engine overnight. AM ambient is about 30 degrees, and everything under the hood is warm. Tested, and NO START. Cabin was at ambient, only under hood components were warm. So, I move the heater to the driver's floor, blowing on the fuse panel. After just 5 minutes, it fires up no problem. Then, next night, it's cold again. I remove the relay from the fuse panel, and bring it inside overnight. I don't plug anything in on the truck. AM, everything is icey, truck is at ambient, cabin and engine. I simply plug the warm relay back into the panel, light the glow plugs for 30 seconds, and it fires right up. Problem solved. Dealers, hope you're PAYING ATTENTION!

 

Good work Chin. Hopefully you didn't pay the dealership for looking over your truck and not solving anything.

Moon

 

What does the relay control ?

 

relay 307 is the a starter relay. As my wife just said that could do it.

 

A post from a long time ago suggested that pulling this relay may be the best (and certainly the cheapest) anti-theft device!! Wouldn't want to do it every time, but it makes sense if the truck would be parked for extended periods or in high risk areas.

 

Hey, good idea... then again, my effective anti-theft device is the 32 foot race trailer that is constantly under tow!

 

You should relay all of this info to Ford when you do your customer satisfaction survey.

 

Ouch !!!!!!!!!!